Fertilizers used in farming add nitrogen and phosphorus to the soil, which help crops grow. But when too much of these nutrients wash off fields and enter rivers and lakes, they can pollute water, harm wildlife, and create large areas with little or no oxygen—known as dead zones. This global problem is getting worse as farming intensifies. In this study, we looked at how much nitrogen and phosphorus from croplands flows into surface waters in 144 countries. We then estimated safe limits for these nutrient levels to prevent water pollution and protect ecosystems. Our findings show that, as of 2020, nitrogen runoff was nearly four times higher than the safe limit, and phosphorus was nearly six times higher. While phosphorus pollution is more severe, reducing nitrogen runoff should be the top priority for controlling water pollution globally. We also analyzed different ways to reduce nutrient runoff and proposed customized strategies for each country. If adopted, these strategies could cut both nitrogen and phosphorus runoff by over 80%. However, regions with high nutrient use and limited resources will face bigger challenges. Coordinated global efforts are urgently needed to protect water quality and the planet’s environmental balance.